Small-amplitude cycles emerge from stage-structured interactions in Daphnia–algal systems

McCauley, Edward; Nelson, William A.; Nisbet, Roger M.

doi:10.1038/nature07220

Cited by 70 publications

(105 citation statements)

References 23 publications

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“…3. Along the stability boundary C 1 we have that π/τ < ω < 2π/τ and so the period of the oscillations is between one and two times the length of the juvenile period at their 'birth' by Hopf bifurcation 5.4 Bistability in both reality and a more complex stage structured model After the finishing of this paper a beautiful paper by McCauley et al (2008) appeared in which a generalisation of the stage structured model of this section was analysed by different means. The authors frame their model as a system of delay-differential equations with variable delay, apply an implicit transformation of the time variable to arrive at a fixed delay and approximate the implicit equation for the probability to survive the juvenile period by a finite system of differential equations.…”

Section: Substrate Serves For Growth Not For Reproductionmentioning

confidence: 99%

Daphnia revisited: local stability and bifurcation theory for physiologically structured population models explained by way of an example

et al. 2009

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We consider the interaction between a general size-structured consumer population and an unstructured resource. We show that stability properties and bifurcation phenomena can be understood in terms of solutions of a system of two delay 254-274, 1984; de Roos et al. in J Math Biol 28:609-643, 1990) and a model introduced by Gurney-Nisbet (Theor Popul Biol 28:150-180, 1985) and Jones et al. (J Math Anal Appl 135:354-368, 1988), and next obtain various ecological insights by analytical or numerical studies of special cases.

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Section: Substrate Serves For Growth Not For Reproductionmentioning

confidence: 99%

Daphnia revisited: local stability and bifurcation theory for physiologically structured population models explained by way of an example

et al. 2009

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“…Age-structured interactions within a host population, coupled with consumer-resource interactions such as predator-prey or host-parasite, can lead to population cycles [20]. In Daphnia-algal systems, these cycles arise owing to competitive interactions between juveniles and adults, and their amplitude is determined by the ratio of the cycle period to juvenile stage duration [21]. Our results indicate that these competitive interactions, through their influence on the host age structure, may feedback on patterns of strain coexistence/exclusion and parasite diversity.…”

Section: Discussionmentioning

confidence: 99%

Host age modulates within-host parasite competition

2015

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In many host populations, one of the most striking differences among hosts is their age. While parasite prevalence differences in relation to host age are well known, little is known on how host age impacts ecological and evolutionary dynamics of diseases. Using two clones of the water flea Daphnia magna and two clones of its bacterial parasite Pasteuria ramosa, we examined how host age at exposure influences within-host parasite competition and virulence. We found that multiply-exposed hosts were more susceptible to infection and suffered higher mortality than singly-exposed hosts. Hosts oldest at exposure were least often infected and vice versa. Furthermore, we found that in young multiply-exposed hosts competition was weak, allowing coexistence and transmission of both parasite clones, whereas in older multiply-exposed hosts competitive exclusion was observed. Thus, agedependent parasite exposure and host demography (age structure) could together play an important role in mediating parasite evolution. At the individual level, our results demonstrate a previously unnoticed interaction of the host's immune system with host age, suggesting that the specificity of immune function changes as hosts mature. Therefore, evolutionary models of parasite virulence might benefit from incorporating age-dependent epidemiological parameters.

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“…Similarly, the densities of many ecological populations oscillate with frequencies that cannot be explained by diurnal, annual, or other seasonal variation (7)(8)(9). Often, such regular oscillations are caused by multispecies interactions (10)(11)(12)(13).…”

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confidence: 99%

Cycles, phase synchronization, and entrainment in single-species phytoplankton populations

Massie

Blasius

Weithoff

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

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Complex dynamics, such as population cycles, can arise when the individual members of a population become synchronized. However, it is an open question how readily and through which mechanisms synchronization-driven cycles can occur in unstructured microbial populations. In experimental chemostats we studied large populations (>10 9 cells) of unicellular phytoplankton that displayed regular, inducible and reproducible population oscillations. Measurements of cell size distributions revealed that progression through the mitotic cycle was synchronized with the population cycles. A mathematical model that accounts for both the cell cycle and population-level processes suggests that cycles occur because individual cells become synchronized by interacting with one another through their common nutrient pool. An external perturbation by direct manipulation of the nutrient availability resulted in phase resetting, unmasking intrinsic oscillations and producing a transient collective cycle as the individuals gradually drift apart. Our study indicates a strong connection between complex within-cell processes and population dynamics, where synchronized cell cycles of unicellular phytoplankton provide sufficient population structure to cause small-amplitude oscillations at the population level.

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Small-amplitude cycles emerge from stage-structured interactions in Daphnia–algal systems

Cited by 70 publications

References 23 publications

Daphnia revisited: local stability and bifurcation theory for physiologically structured population models explained by way of an example

Daphnia revisited: local stability and bifurcation theory for physiologically structured population models explained by way of an example

Host age modulates within-host parasite competition

Cycles, phase synchronization, and entrainment in single-species phytoplankton populations

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